Cell phones, particularly smart phones, are becoming more ubiquitous and versatile. As demand grew, cell phones design also grew to support more security features, such as a lock. When a user is not using the cell phone, the user may lock the phone to prevent others from having full access to all its features and information. When the user wishes to use the cell phone, the user may unlock the phone by entering a code.
However, it may not always be safe for the user to unlock the phone. For example, other people may be looking at the user to steal the code as the user enters it. Furthermore, the user may leave prints or smudges that another person could use to steal the code.